Filtering in Doom: None or Bi/Trilinear?

[DANZA]

3 hours ago, cyan0s1s said:

RetroShader might be to your liking for G/QZDoom.

Didn´t know about it. It's kind of redundant with it being more software like than the actual software source ports, but it has some "psx moving polys" charm. Thanks!

[<inactive>Player Lin]

Screw those ****ing filtering bullshit at all, I want my sprites just clearly, not blurred shit(even it would be better than not filtering)...but at least in sprites-based FPS games like DooM or Duke3D. :p

[Spie812]

I just wanted to write something a bit more comprehensive than just a short 1-sentence answer.

 

Here is a direct comparison of the most common filtering choices:

All 5 images were taken at the exact same spot on E3M6. I chose this wall because the skulls going off into the distance provide a good measure of quality.

Spoiler

 

 

None: The classic DOOM option, which uses no filtering whatsoever. Naturally, doing no filtering causes problems. Things at a distance tend to devolve into a pixelated mess, which can be seen somewhat in the screenshot. Much harder to capture in a screenshot, however, is the 'pixel swimming' that you see when moving around even a tiny bit. It's not a good option, but it's fast and some people prefer it because of it's similarity to classic DOOM.

 

Nearest Mipmap: I don't know why this option is popular at all. Everything it does is done better by the 'linear mipmap' option. Anyway, adding mipmaps to the mix solves the problem of the pixelated mess and pixel swimming when you don't use any sort of filtering. However, it poses it's own problem of clear 'quality lines' at the borders of one mipmap and the next. Also, mipmaps are isotropic, so you get a severe loss of quality when looking at steep angles (a problem that persists even in more advanced options.)

Linear Mipmap:  Everything that 'nearest mipmap' is but better. Interpolating between mipmaps is a bit slower than using the mipmaps alone, but it completely gets rid of the 'quality line' problem. If someone is unable (or unwilling) to use anisotropic filtering, this is the option that I would recommend.

 

Trilinear: Probably the most common choice overall, but I hate it. Everything is so blurry! However, some people do prefer the look of the blurriness. Also, it is the default option in most GL ports because it is an excellent showcase of what the ports can add to the look and feel of DOOM.

 

None (Trilinear) + 16x Anisotropic Filtering: Well, that's a mouthful, isn't it? I'm including this because this is what I use. Anisotropic filtering effectively gets rid of the loss of quality at steep angles. It is objectively the clearest option in the set. Every texture is crisp and well-defined even at far-away distances or at steep angles. Some people may prefer the pixely look of 'none' or the blurry look of 'trilinear.' It really is a matter of personal tastes. However, if you are one for clarity and sharpness in your textures like me, this is the option to use.

Glboom+ doesn't have an equivalent to 'none (trilinear)' to pair with the anisotropic filtering, so I use linear mipmap+anisotropic filtering in that port instead, which yields similar results.

 

[Nevander]

35 minutes ago, Spie812 said:

but it completely gets rid of the 'quality line' problem. If someone is unable (or unwilling) to use anisotropic filtering, this is the option that I would recommend.

This is the problem I have with my video drivers. The quality line thing stays even if you use anisotropic filtering or linear mipmap in GZDoom. GZDoom Builder seems to do the same thing too. Really off-putting so I have to use no filtering whatsoever.

[dugan]

The Brutal DOOM trailers sold me on Nearest (with linear mipmaps).